The present invention relates to a swingable or pivotal support leg for a bridge, especially for a portable bridge of the type having pivotal support legs provided with pivotally connected foot members at the free end thereof.
German Offlengungsschrift No. 2,019,985 discloses a support leg for bridges which has a pivotally connected foot member. This foot member consists of a one-part plate which is swingable within narrow limits for accommodating uneven ground support.
FR-PS No. 87,029 discloses a support leg for transportable bridges which is pivotal so as to be swingable into a transport storage position. This arrangement is also provided with a foot member consisting of a one-piece plate.
The above-noted arrangements exhibit disadvantages in that the foot member, during pivoting inwardly of the support leg into a transport position, projects under the bridge requiring additional space. Further, when picking up a number of bridge portions to be stacked one above the other, the protruding supporting leg foot member substantially hinders the loading and unloading processes.
The present invention contemplates apparatus which overcomes the above-noted disadvantages. More specifically, the present invention contemplates providing a foot member for a swingable support leg for bridges which, during the pivoting inwardly of the support leg under the bridge, is placed at the bridge under-side in a space saving manner.
According to preferred embodiments of the invention, the foot member is formed of plate members arranged cross-wise to the longitudinal direction of the bridge, and which are pivotable with respect to one another. These plate members are supported in an intermediate support member at the free end of the support leg and are forcibly pivoted together by means of a control lever. With this arrangement, during swinging inward movement of the support leg to a transport position, the plate members of the foot are folded so as to be arranged in a space saving manner as a continuation of the longitudinal extent of the support leg. In other words, the plate members are movable from an in-use position extending transversely to the longitudinal extent of the support leg to a storage position extending in the longitudinal direction of the support leg, whereby the lateral dimensions in the storage position are substantially reduced as compared to the lateral dimensions in the support in-use position.
In a particularly preferred embodiment of the invention, the plate members are pivotally connected at respective pivot means of the intermediate support member and the control lever interconnecting the plate members is pivotally connected at one of the plate members above the pivot connection thereof at the intermediate support member and at the other plate member below the respective pivot connection thereof at the intermediate support member. In this manner a very simple reliable forced simultaneous pivoting of the plate members with respect to the intermediate support members is effected. That is, by the specific placement of the pivot connections for the control lever with respect to the pivot connections of the plate members at the intermediate support member, the pivotal movement of one of the plate members automatically results in a simultaneously oppositely directed pivotal movement of the other plate member.
For assuring movement of the plate members from the storage position to the in-use position, the present invention contemplates the provision of elastic band means attached to the upper sides of the plate members, which elastic band continually applies a force tending to move the plate members to the in-use position extending transversely of the longitudinal extent of the support leg.
The present invention further provides that the plate members abuttingly engage respective opposite support edges of the intermediate support member when in the in-use position, with the support edges and the plate members including interengaging cam and notch means so as to create a stiff plate composed of the plate members and intermediate support members. In preferred embodiments, cams are provided at the plate members which engage in notches at the side edges of the intermediate support member.
To accommodate reliable forceful pivoting of the plate members to the storage position during the pivotal storage of the support leg against the bridge portion, the present invention further contemplates the provision of rollers arranged at the free ends at the top side of the plate members, which rollers engage in guide tracks at the bridge portion and apply plate member folding forces as the support leg is pushed against the brigde portions.
These and further objects, features and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, one embodiment in accordance with the present invention .